Bondline control fixture and method of affixing first and second components

ABSTRACT

A bondline control fixture and an active bondline control fixture are provided for affixing first and second components. The bondline control fixture includes a base fixable relative to a first component maneuvering device and comprising a first body defining an aperture and a first chamber and a second body disposable within the first chamber and defining a second chamber, a flexible membrane disposable to seal the second chamber, a mobile plate to which the second component is removably attachable, the mobile plate being disposable in contact with the flexible membrane and a pressure regulating system coupled to the second body and configured to regulate a pressure within the second chamber to deform the flexible membrane.

BACKGROUND

The present invention relates to assembly of micro-electronics,opto-electronics and photo-electronics and, more particularly, to abondline control fixture, an active bondline control fixture and amethod of passively or actively affixing first and second components.

In various technologies, there is frequently a need for attaching twostandard pick and place components together. In some cases, thecomponents may include a flexible polymer component with a standardoptical interface and polymer waveguides extending outwardly from a sideof the interface along a lower surface of a compliant extension and aphotonic integrated circuit (IC) with photonic IC waveguides on an uppersurface of a complementary metal-oxide-semiconductor (CMOS) element.Previously, one of the components has been picked up with a picker armand placed on the other component with that other component residing ona base. Both the picker arm and the base may move in X-, Y- andZ-directions in order to position the components with respect to eachother.

However, no specific control is used to ensure that the parallelismbetween the picker arm and base surfaces is tightly controlled. In thecase of the components being the flexible polymer component and thephotonic integrated circuit (IC), this lack of parallelism impedes theenablement of an adiabatic coupling of light signals from the polymerwaveguides to the photonic IC waveguides.

SUMMARY

According to an embodiment of the present invention, a bondline controlfixture for affixing first and second components is provided. Thebondline control fixture includes a base fixable relative to a firstcomponent maneuvering device and comprising a first body defining anaperture and a first chamber and a second body disposable within thefirst chamber and defining a second chamber, a flexible membranedisposable to seal the second chamber, a mobile plate to which thesecond component is removably attachable, the mobile plate beingdisposable in contact with the flexible membrane and a pressureregulating system coupled to the second body and configured to regulatea pressure within the second chamber to deform the flexible membrane.

According to another embodiment, an active bondline control fixture foraffixing first and second components is provided and includes a basefixable relative to a first component maneuvering device, the basedefining an aperture and a chamber, a mobile plate to which the secondcomponent is removably attachable, the mobile plate being disposable atleast partly in the aperture and an actively controllable actuationsystem configured to adjust an altitude of the mobile plate relative tothe base in accordance with a degree of parallelism between the firstand second components.

According to yet another embodiment, a method of passively or activelyaffixing first and second components is provided. The method includessupporting a mobile plate on a base fixable relative to a firstcomponent maneuvering device, removably attaching the second componentto the mobile plate, dispensing adhesive on either the first or thesecond component, maneuvering the first component toward the secondcomponent with the first component maneuvering device and manipulatingthe mobile plate to increase a degree of parallelism between the firstand second components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view of an apparatus in accordance withembodiments;

FIG. 2 is a perspective view of a bondline control fixture in accordancewith embodiments;

FIG. 3 is a cutaway view of the bondline control fixture of FIG. 2;

FIG. 4 is an enlarged side view of a portion of the bondline controlfixture of FIG. 3;

FIG. 5A is a side view of first and second components being broughttogether in a non-parallel orientation;

FIG. 5B is a side view of the first and second components being broughttogether in a parallel orientation;

FIG. 6A is a side view of first and second components being broughttogether in a non-parallel orientation;

FIG. 6B is a side view of the first and second components being broughttogether in the non-parallel orientation with a flexible membrane beinginflated;

FIG. 6C is a side view of the first and second components being broughtinto contact in the non-parallel orientation with the flexible membranebeing inflated;

FIG. 6D is a side view of the first and second components in contact ina parallel orientation with an inflated flexible membrane beingdeformed;

FIG. 6E is a side view of the first and second components in contact inthe parallel orientation with the inflated flexible membrane beingfurther deformed; and

FIG. 7 is a side view of an active bondline control fixture inaccordance with embodiments.

DETAILED DESCRIPTION

As will be described below, a passive or active bondline control fixtureis provided for passively or actively increasing a degree of parallelismbetween first and second pick and place components, such as a flexiblecomponent with a standard optical interface and polymer waveguides nearthe side of the interface along a lower surface of a compliant extensionand a photonic integrated circuit (IC) with photonic IC waveguides nearan upper surface. The photonic IC could be a complementarymetal-oxide-semiconductor (CMOS) element. Use of the passive or activebondline control fixture allows the first component to be affixed to thesecond component so that efficient optical coupling of light signalsfrom the waveguides of the first component to the photonic IC waveguidesof the second component is enabled without need for micro-adjustments ofa picker arm of the first component. Various light coupling schemescould be used such as adiabatic coupling, directional, coupling or buttcoupling.

With reference to FIG. 1, an apparatus 1 is provided for bringingtogether and affixing to one another standard pick and place fixturessuch as a first component 2 and a second component 3. The apparatus 1generally includes a picker arm 4 that is configured to pick up andmaneuver the first component 2 by way of vacuum pressure and a base 5,which is fixed relative to ground and the picker arm 4 and on which thesecond component 3 is mounted and held by vacuum pressure. Duringoperation, a tip 400 of the picker arm 4 contacts the first component 2and a vacuum 401 of the picker arm 4 engages to permit the picker arm 4to lift the first component 2. The picker arm 4 then moves the firstcomponent 2 in the X- and Y-directions until the first component 2 ispositioned over the second component 3. Next, the picker arm 4 moves thefirst component 2 in the Z direction toward the second component 3 untilthey come into contact. Upon contact, adhesive between the first andsecond components 2 and 3 is permitted to cure.

In accordance with embodiments, the first component 2 may be, forexample, a flexible polymer component with a standard optical fiberinterface and polymer waveguides near the side of the interface along alower surface of a compliant extension. The second component may be, forexample, a photonic integrated circuit (IC) with photonic IC waveguideson an upper surface. The photonic IC can be a complementarymetal-oxide-semiconductor (CMOS) element. In affixing the firstcomponent 2 to the second component 3, efficient coupling of lightsignals from the polymer waveguides of the first component 2 to thephotonic IC waveguides of the second component 3 is enabled. However,achieving such an enabling configuration requires that a distance orZ-gap between the first and second components 2 and 3 be very small andwell controlled (e.g., less than two microns and preferably less thanone micron level) along a significant area of proximity between thefirst and second components 2 and 3. This area includes notable extentsof waveguides placed at the surface or in proximity of the surface onboth the first and second components 2 and 3.

Thus, with reference to FIGS. 2-4, 5A and 5B and 6A-6E, a bondlinecontrol fixture 10 is provided and is capable of making and adjusting aparallelism of standard pick and place fixtures (i.e., the first andsecond components 2 and 3 of FIG. 1) to the tolerances needed to enableefficient coupling of the light signals from waveguides of the firstcomponent 2 to the photonic IC waveguides of the second component 3. Tothis end, the bondline control fixture 10 includes a base 20, a flexiblemembrane 30 (see FIGS. 3-5A and 5B), a mobile plate 40 and a pressureregulating system 50 (see FIG. 3). The base 20 is fixable relative toground and a first component maneuvering device (i.e., the picker arm 4of FIG. 1) and includes a first body 21 and a second body 22.

The first body 21 may be generally volumetric with sidewalls 210 and anupper work surface 211 that is supported on the sidewalls 210. Thesidewalls 210 and the upper work surface 211 cooperatively define anaperture 212, a first chamber 213 and a groove 214. The upper worksurface 211 has an inwardly facing surface 2110 and a flange 2111 thatextends inwardly from an upper portion of the inwardly facing surface2110. The aperture 212 is generally defined in a plane of the upper worksurface 211 by the inwardly facing surface 2110 and the flange 2111. Theflange 2111 has a lower surface 2112. The first chamber 213 is generallydefined below the aperture 212 and the plane of the upper work surface211 and is delimited by interior facing surfaces of the sidewalls 210and the upper work surface 211. The groove 214 is generally defined inthe plane of the upper work surface 211 and is communicative with theaperture 212.

The second body 22 is disposable within the first chamber 213 of thefirst body 21 and includes a main body 220 formed to define an inlet 221and having an upper surface 222 and a peripheral ridge 223. Theperipheral ridge 223 runs along a periphery of the upper surface 222such that the peripheral ridge 223 and a central section of the uppersurface 222 define a second chamber 224, which is fluidly communicativewith the inlet 221.

The flexible membrane 30 may be formed of rubberized material and isdisposable to seal the second chamber 224. The flexible membrane 30includes a first section 31 and a second section 32 and has a thicknessthat is substantially similar to a distance between the interior facingsurface of the upper work surface 211 of the first body 21 and theperipheral ridge 223 of the second body 22. The first section 31 isinterposable and tightly fittable between the first and second bodies 21and 22 and, in particular, between the interior facing surface of theupper work surface 211 of the first body 21 and the peripheral ridge 223of the second body 22. The second section 32 is defined within the firstsection 31 and is thus disposable to seal or in some cases hermeticallyseal the second chamber 224. With the second chamber 224 pressurized atatmospheric pressure, an upper surface 310 of the flexible membrane 30may be substantially coplanar with a plane of the interior facingsurface of the upper work surface 211.

The mobile plate 40 is disposable within the first chamber 213 of thefirst body 21 and in the aperture 212. The mobile plate 40 includes abody having an exterior facing surface 410 and a footer 411. The footer411 extends outwardly from a lower portion of the exterior facingsurface 410 and has an upper flange surface 412. The lower surface 2112of the flange 2111 of the upper work surface 21 and the upper flangesurface 412 overlap with one another such that, as the mobile plate 40is raised, the upper flange surface 412 contacts the lower surface 2112to thereby limit an upward motion of the mobile plate 40.

The mobile plate 40 is disposable in contact with the upper surface 310of the flexible membrane 30. As such, the mobile plate 40 effectivelyfloats on the flexible membrane 30 and can be maneuvered or re-orientedin accordance with a condition of the flexible membrane 30.

The mobile plate 40 further includes an uppermost surface 413 on which,e.g., the second component 3 of FIG. 1 is removably attachable by wayof, for instance, vacuum pressure. This vacuum pressure may be generatedby a vacuum system 42 including a hose 420 that extends along the groove214. In addition, adhesive may be dispensed on the uppermost surface 413to increase a degree of bonding of the second component 3 to theuppermost surface 413.

The pressure regulating system 50 is coupled to the second body 22 andis configured to regulate a pressure within the second chamber 224 thatis sufficient to deform the flexible membrane 30 toward the mobile plate40 or to permit deforming of the flexible membrane 30 in the oppositedirection. In accordance with embodiments, the pressure regulatingsystem 50 may include a hose 51, which is coupled to the inlet tothereby direct pressurizing fluid into the second chamber 224, and, insome cases, a controller 52. Where the pressure regulating system 50includes the controller 52, the controller 52 monitors a pressure withinthe second chamber 224 and increases or decreases the pressure inaccordance with a compressive force between the first and secondcomponents 2 and 3 and cure characteristics of any adhesive used betweenthe first and second components 2 and 3. In the case where the pressurewithin the second chamber 224 is sufficient to deform the flexiblemembrane 30 toward the mobile plate 40, the pressure has to be limitedto such a level that the compressive force between the first and secondcomponents 2 and 3 will be sufficient to push down the upper flangesurface 412 of the mobile plate 40 off its resting position against thelower surface 2112 of the upper work surface 211 of the first body 21.

With reference to FIGS. 5A and 5B, in one embodiment, the flexiblecharacteristic of the flexible membrane 30 and the pressure within thesecond chamber 224 permits a certain degree of rotational ortranslational movement of the mobile plate 40 within the aperture 212.In such cases, as the first and second components 2 and 3 are broughttogether in a non-parallel orientation (see FIG. 5A), the flexiblemembrane 30 deforms downwardly, which can in some cases result inreducing a volume of the second chamber 224. This causes the mobileplate 40 to rotate to therefore bring the first and second components 2and 3 into a more parallel orientation.

As shown in FIGS. 6A-6E an alternative operation of the bondline controlfixture 10 as described above will now be described. In this embodiment,the second chamber 224 is pressurized to inflate the flexible membrane30. The flexible membrane 30 is thus deformed or curved upwardly and tocreate a tangential contact between the upper surface 310 of theflexible membrane 30 and the mobile plate 40. Such tangential contactpermits a certain degree of rotational or translational movement of themobile plate 40 within the aperture 212 to the extent permitted by theinterference between the upper flange surface 412 of the mobile plate 40and the lower surface 2112 of the upper work surface 211 (which has thesecondary result in an increased contact area between the mobile plate40 and the flexible membrane 30).

At an initial time, as shown in FIG. 6A, the first and second components2 and 3 are brought toward one another with the second chamber 224un-pressurized and the flexible member 30 un-deformed. Then, as shown inFIG. 6B, the second chamber 224 may be pressurized such that the mobileplate 40 will be urged upwardly until the upper flange surface 412 restsagainst the lower surface 2112. Next, as shown in FIG. 6C, the first andsecond components 2 and 3 are brought together in the Z-direction and ina non-parallel relative orientation.

As the first and second components 2 and 3 continue to come intocontact, as shown in FIGS. 6D and 6E, the compressive forces between thefirst and second components 2 and 3 exceed the pressure generated withinthe second chamber 224 and the mobile plate 40 is forced downwardly suchthat the upper flange surface 412 recedes from the lower surface 2112.In this condition, the mobile plate 40 is effectively rotated along theupper surface 310 of the flexible membrane 30, which will benon-uniformly deformed. This rotation of the mobile plate 40 brings thefirst and second components 2 and 3 into a parallel relative orientationwithout requiring any micro-adjustments being made by the firstcomponent maneuvering device (i.e., the picker arm 4 of FIG. 1). Oncethe parallel relative orientation is achieved with the first and secondcomponents 2 and 3 in contact, the adhesive used between the first andsecond components 2 and 3 can be cured.

For instance, an optically transparent UV-curable adhesive could beused. The optical transparence should be to the wavelength of the lightsignals coupled between component 2 and 3 and is important to minimizeoptical coupling loss. A refractive index of the adhesive should bebelow a refractive index of a waveguide on component 2. A UV-curableadhesive could improve throughput via fast tacking or cure compared witha thermally cured adhesive.

It will be appreciated that the second chamber 224 can be pressurizedprior to assembly to a level not forcing plate 40 to fully rest upperflange surface 412 on lower surface 2112. The contact between 412 and2112 prior to assembly can full, partial or none. The amount of pressurein chamber 224 depends on the desired assembly force and the resultingdesired assembly pressure between component 2 and 3. The desiredassembly pressure is a function of the viscosity of the adhesive and thestiffness and mechanical robustness of components 2 and 3. The largerthe adhesive viscosity and the larger the component stiffness andmechanical robustness, the larger the desired assembly force.

With reference to FIG. 7, an active bondline control fixture 100 isprovided for affixing the first and second components 2 and 3. Theactive bondline control fixture 100 includes similar features as thoseof the bondline control fixture 10 described above and a detaileddescription of those features will be omitted. The active bondlinecontrol fixture 100 includes a base 110, which is fixable relative to afirst component maneuvering device (i.e., the picker arm of FIG. 1) andwhich defines an aperture 111 and a groove 112 in an upper work surface113 thereof and a chamber 114, a mobile plate 120 and an activelycontrollable actuation system 130. The second component 3 is removablyattachable to the mobile plate 120 by way of vacuum pressure and ismovably (i.e., rotatably or translationally) disposable at least partlyin the aperture 111. The actively controllable actuation system 130 isconfigured to adjust an attitude of the mobile plate 120 relative to thebase 110 in accordance with a degree of parallelism between the firstand second components 2 and 3.

In accordance with embodiments, the actively controllable actuationsystem 130 includes a plurality of actuators 131. The actuators 131 aredisposed within the chamber 114 and are respectively coupled at firstends thereof to the base 110 and at second ends thereof to localportions 121 of the mobile plate 120. The actuators 131 may be providedas linear actuators that can extend or retract in the Z-direction andthus may be configured to adjust distances between the base 110 and thelocal portions 121 of the mobile plate 120. In accordance withembodiments, the actuators 131 may be provided in a group of threeactuators 131 that are arranged in a triangular formation. As such, byincreasing or decreasing the distances between the base 110 and thelocal portions 121, the actuators 131 can control an attitude of themobile plate 120 relative to the base 110.

As shown in FIG. 7, the actively controllable actuation system 130 mayinclude a controller 132 that is respectively coupled to each of theactuators 131 and a sensor 133. The sensor 133 may be disposed to sensethe degree of parallelism between the first and second components 2 and3 and may be provided as a pressure sensor at each of the actuators 131.The sensor 133 could thus identify when the first and second components2 and 3 are brought together in a non-parallel relative orientationsince initial contact between the non-parallel first and secondcomponents 2 and 3 will read as a high pressure input at the actuator131 proximate to a “low” side of the first component 2 and as a low orzero pressure input at the actuator 131 proximate to the “high” side.

The controller 132 may include a processing unit 1320 disposed in signalcommunication with the sensor 132, a memory unit 1321 and servocontrollers 1322 that are respectively coupled to each of the actuators131. The memory unit may have executable instructions stored thereon,which, when actuated, cause the processing unit to receive pressurereadings from the sensor 132 of the actuators 131, to determine fromthose pressure readings a degree of non-parallelism between the firstand second components 2 and 3, to determine a corrective action neededto increase the degree of parallelism and issue commands to the servocontrollers in accordance with the determined corrective action. Theservo controllers may then control the actuators 131 and, in particular,may control the actuator 131 associated with the high pressure readingto retract. In so doing, the controller 132 will thereby lower themobile plate 120 at the “low” side and to in turn increase the degree ofparallelism between the first and second components 2 and 3.

In accordance with aspects, a method of passively or actively affixingthe first and second components 2 and 3 to one another is provided. Themethod includes supporting the mobile plate 40/120 on the base 20/110,which is fixable relative to a first component maneuvering device (i.e.,the arm picker 4 of FIG. 1), removably attaching the second component 3to the mobile plate 40/120, maneuvering the first component 2 toward thesecond component 3 with the first component maneuvering device andpassively or actively manipulating the mobile plate 40/120 to increase adegree of parallelism between the first and second components 2 and 3.In accordance with embodiments, the passive manipulating may includedeforming the flexible membrane 30 whereas the active manipulating mayinclude adjusting the distance between the mobile plate 120 and the base110.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of onemore other features, integers, steps, operations, element components,and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

While the preferred embodiment to the invention had been described, itwill be understood that those skilled in the art, both now and in thefuture, may make various improvements and enhancements which fall withinthe scope of the claims which follow. These claims should be construedto maintain the proper protection for the invention first described.

What is claimed is:
 1. A bondline control fixture for affixing first andsecond components, the bondline control fixture comprising: a basefixable relative to a first component maneuvering device and comprisinga first body defining an aperture and a first chamber and a second bodydisposable within the first chamber and defining a second chamber; aflexible membrane disposable to seal the second chamber; a mobile plateto which the second component is removably attachable, the mobile platebeing disposable in contact with the flexible membrane; and a pressureregulating system coupled to the second body and configured to regulatea pressure within the second chamber to deform the flexible membrane. 2.The bondline control fixture according to claim 1, wherein the firstcomponent comprises a flexible polymer component and the secondcomponent comprises a photonic integrated circuit.
 3. The bondlinecontrol fixture according to claim 1, wherein the first body comprisessidewalls and a work surface supportable on the sidewalls, wherein thework surface is formed to define the aperture and a groove incommunication with the aperture.
 4. The bondline control fixtureaccording to claim 1, wherein the flexible membrane comprises: a firstsection interposable between the first and second bodies; and a secondsection disposable to hermetically seal the second chamber.
 5. Thebondline control fixture according to claim 1, wherein the flexiblemembrane comprises rubberized material.
 6. The bondline control fixtureaccording to claim 1, wherein the mobile plate is sized to movably fitwithin the aperture.
 7. The bondline control fixture according to claim1, wherein the mobile plate is sized to rotatably fit within theaperture.
 8. The bondline control fixture according to claim 1, whereinthe second component is vacuumed onto the mobile plate and adhesive isdispensed on its top surface.
 9. An active bondline control fixture foraffixing first and second components, the active bondline controlfixture comprising: a base fixable relative to a first componentmaneuvering device, the base defining an aperture and a chamber; amobile plate to which the second component is removably attachable, themobile plate being disposable at least partly in the aperture; and anactively controllable actuation system configured to adjust an attitudeof the mobile plate relative to the base in accordance with a degree ofparallelism between the first and second components.
 10. The activebondline control fixture according to claim 9, wherein the activelycontrollable actuation system comprises actuators disposed within thechamber that are each coupled to the base and a local portion of themobile plate and configured to adjust a distance between the base andthe local portion.
 11. The active bondline control fixture according toclaim 10, wherein the actively controllable actuation system comprises acontroller coupled to each actuator and configured to control anoperation of each actuator in accordance with the degree of parallelism.12. The active bondline control fixture according to claim 11, whereinthe actively controllable actuation control system comprises a sensordisposed to sense the degree of parallelism.
 13. The active bondlinecontrol fixture according to claim 12, wherein the actively controllableactuation control system comprises a pressure sensor at each of theactuators.
 14. The active bondline control fixture according to claim10, wherein the actuators are arranged in a triangular formation. 15.The active bondline control fixture according to claim 10, wherein eachactuator comprises a linear actuator.
 16. The active bondline controlfixture according to claim 9, wherein the mobile plate is sized tomovably fit within the aperture.
 17. The active bondline control fixtureaccording to claim 9, wherein the mobile plate is sized to rotatably fitwithin the aperture.